The present invention relates to apparatus employed for molding and freezing confectionery substances to obtain frozen confectionery articles and particularly, to making multi-component confectionery articles with devices which meter products to molds for making the articles and with devices for suctioning products from the molds and to recycling suctioned product for reuse.
The production of molded articles of frozen confectionery in individual portions, in particular stick ice lollies, composed of several differently flavoured concentric layers, requires the use of the so-called "shell and core" technique. It consists of allowing a certain thickness of a liquid composition to harden towards the centre by heat transfer from the outside of a mold in contact with a refrigerating liquid, and of emptying the as yet unsolidified central part by suction. Accordingly, a solid shell remains at the periphery, empty in the centre. A new operation combining metering, hardening into a layer and suction can be carried out several times in this way. This technique is currently used for the manufacture of water ice lollies by molding.
A process is known, for example from European Patent Application Publication No. 0 322 469, for manufacturing a multi-layer molded frozen article including inside it alternate layers of ice cream and chocolate leaves in the form of a shell. In this process, the successive alternate layers of ice cream and chocolate are created by filling molds, solidifying the periphery, withdrawing the still liquid centre, spraying chocolate into the central cavity and repeating the preceding filling and withdrawal operations. The devices enabling filling and withdrawal to be carried out are not described, but it is clear that they operate separately. Moreover, it is not specified that the liquid withdrawn is recycled.
The manufacture of molded chocolate shells by filling cells, solidifying the periphery and then withdrawing the centre is described, for example, in U.S. Pat. No. 3,529,553. Although the liquid withdrawn is recycled by means of a pump to the feed hopper, filling and withdrawal are carried out separately by means of distinct devices.
A need is felt to improve the quality and production efficiency of articles of this shell-and-core type as well as a need to obtain better cleaning hygiene.
Up to now, the aspiration technique generally used for simplifying manufacture and improving cleaning hygiene has consisted of profiting from the principle of volumetric metering by means of a piston moving inside a filling chamber with one metering unit per filling line, and a filling line which can comprise as many as 20 tracks. The filling chamber is connected to a pipette by a pipe and via valves and the pipette dips into the centre of the mold. Coordination is achieved by means of a mechanical linkage in two stages. In a first stage, a relative movement of the piston in its chamber produces a vacuum and liquid is pushed up inside the chamber under the effect of ambient air pressure, filling coming to an end when the piston arrives at the end of the stroke at the bottom of the chamber. In a second stage, the pipette leaves the mold as the movement of the piston in the chamber reverses, and due to the valves, liquid is expelled into a second pipe and is hence recycled, either into an intermediate buffer reservoir or directly into the metering hopper the latter containing recycled liquid and fresh liquid added in a quantity corresponding to the volume already metered. The success of the operation depends on the system being completely liquid-tight. The degree of maintenance and care to be taken over cleaning as many systems as there are tracks, multiplied by the number of suction operations required, dictated by the nature of the composite product to be manufactured, is considerable. These difficulties explain why this system is only used for metering nonviscous syrups constituting compositions for water ices.